use std::{collections::HashMap, clone};


// 求最长子字符串
pub fn longest_sub_str(s: &str) -> (Option<String>, u32) {
    let mut subs = String::new();
    let mut length = 0;
    if s.len() == 0 {
        return (None, 0);
    }

    let mut count:HashMap<&char, u32> = HashMap::new();
    let mut i = 0;
    let mut j= -1;
    let mut countDup = 0;
    for c in s.chars() {
        // let mut e = count.entry(c).or_insert(1);

    }

    (Some(subs), length)

}